Alzheimer's Disease is distinguished by the accumulation of extracellular amyloid deposits and intracellular neurofibrillary tangles; recently transgenic mice have been engineered that develop amyloid deposits in an age-dependent fashion. In this collaboration we use multiphoton microscopy on living transgenic mice to visualize and study the in vivo kinetics of amyloid deposition, to test directly the hypothesis that deposited amyloid is cleared in vivo, and to monitor the level of oxidative stress near plaque deposits and plaque cores.